MAX-phase ceramic microscopic structure edited composite material as well as preparation method and application of MAX-phase ceramic microscopic structure edited composite material

Abstract

The invention belongs to the technical field of inorganic materials, and particularly relates to an MAX-phase ceramic microstructure edited composite material and a preparation method and application thereof. The composite material comprises an MAX phase and a metal boride phase, the molecular formula of the MAX phase is M2AX, and the molecular formula of the metal boride phase is MeB2. A boride MAX material, an M ''material and an X material are used as raw materials, and are subjected to in-situ sintering at high temperature and high pressure to obtain the material. According to the preparation method, crystal lattice editing is carried out on a parent phase under a high-temperature condition, meanwhile, a metal boride reinforced phase grows in situ, and in the process, the nucleation position and the material source of the metal boride are accurately controlled by the editing process, so that directional regulation and control on the shape of the reinforced phase are realized. Compared with an MAX phase or metal boride ceramic material, the mechanical property of the obtained composite material is remarkably improved, and the composite material has wide application prospects in the extreme environment fields of advanced nuclear energy, aerospace, maritime work equipment and the like.

Description

Technical Field

[0001] This invention belongs to the field of inorganic materials technology, specifically relating to a composite material with MAX phase ceramic microstructure editing, its preparation method, and its application. Background Technology

[0002] MAX phases are a class of ternary layered crystalline materials with a hexagonal crystal system and space group P63 / mmc. Their chemical composition can be represented as M n+1 AX n The general molecular formula is given by M, where M is a pre-transition metal, A is usually a group IIIA or IVA element, X is usually carbon or nitrogen, and n takes the value 1, 2, or 3. The crystal structure of the MAX phase is generally considered to be composed of M... n+1 X n The MAX phase is formed by alternating stacking of nanostructured sublayers and A-site monolayers. MAX phase layered materials possess advantages such as high temperature resistance, high damage tolerance, thermal shock resistance, and ease of processing. Compared to traditional transition metal carbide and nitride ceramics, MAX phase materials exhibit superior fracture toughness; simultaneously, their unique layered structure and moderate hardness provide excellent machinability, overcoming the limitations of traditional ceramics in terms of machining. Compared to traditional aluminum alloys and other metallic materials, MAX phase materials possess superior high-temperature mechanical properties, maintaining a high modulus at 1000 °C and exhibiting good oxidation resistance at high temperatures. Traditional metallic materials have low hardness and are prone to failure in abrasive environments; MAX phases combine high hardness with a low coefficient of friction, resulting in superior wear resistance. Therefore, MAX phase materials have the potential for application in extreme environments such as nuclear accidents and aerospace. Due to the presence of highly electronegative non-metallic atoms occupying the A-sites, the MA bonds in covalent MAX phases exhibit significant covalent characteristics, leading to a fundamental difference in their electronic structure and chemical bonding compared to traditional metallic MAX phases. Strong covalent bonds make the crystal structure of materials more stable, resulting in superior hardness and strength, as well as stronger corrosion resistance. Covalent MAX phases show promising application prospects in structural materials.

[0003] Chalcogenide MAX phases are an important class of covalent MAX phase materials. Due to the occupancy of chalcogenide elements (S, Se, Te) at the A-site, the MA bonds possess higher strength, exhibiting higher Young's modulus and shear modulus, as well as stronger corrosion resistance. Zr₂SeC is a novel chalcogenide MAX phase. Se atoms have a larger size and lower electronegativity than S atoms, resulting in weaker localization of outer electrons between MA atoms after Se atoms occupy the A-layer. Therefore, the electron contribution portion of the thermal conductivity of Zr₂SeC is significantly activated at 450 K, thus compensating for the decreasing trend of thermal conductivity at high temperatures. However, the directionality of the covalent bonds in chalcogenide MAX phases restricts dislocation slip and multiplication, leading to lower fracture toughness than metallic MAX phases. Under strong load impacts, cracks are more likely to initiate, causing chalcogenide MAX phase materials to fail.

[0004] In the field of ceramic matrix composites, toughening methods mainly include second-phase reinforcement, phase transformation toughening, in-situ self-generated toughening, and nano-toughening. Currently, research on MAX phase ceramic matrix composites is relatively limited and focuses on using inorganic fibers as toughening phases in MAX phase ceramics. For example, Xiong et al. (Y. Xiong et al., Int. J. Appl. Ceram. Technol (2021, 19, 545-556) SiC was prepared by HIP hot pressing method. f The Ti3SiC2 composite material, with fiber toughening, achieved a fracture toughness of 6.76 MPa·m. 1 / 2 The fracture toughness of its matrix material, Ti3SiC2 ceramic bulk, is 5.97 MPa·m. 1 / 2 This represents a 13% improvement compared to the previous method; however, severe thermal mismatch between the fiber and the matrix leads to intractable porosity problems. But Bucevac et al. (D. Bucevac et al., Ceram. Int. (2010, 36, 2181-2188) In-situ TiB2 particle-toughened SiC ceramics were prepared. The in-situ generated TiB2 particles improved the sintering driving force, further densifying the ceramic material. At the same time, TiB2 particles could exert multiple toughening mechanisms, increasing the fracture toughness of the SiC-based composite material to 5.7 MPa·m. 1 / 2 The fracture toughness of SiC ceramics is 4.7 MPa·m. 1 / 2This represents a 21% improvement. In-situ self-growing toughening addresses the problem of material failure caused by internal voids and microcracks resulting from the difference in thermal expansion coefficients between the matrix and the reinforcing phase during sintering. This toughening method has become an important pathway for realizing the application of chalcogenide MAX phases. Although this method can achieve in-situ growth of the TiB2 second phase, its microstructure is mostly coarse-grained, leading to poor toughening effect. Currently, there are few reports on how to directionally optimize the microstructure of ceramic composites (especially MAX phase ceramic composites) by controlling the growth of second-phase grains, and ultimately improve their fracture toughness. Summary of the Invention

[0005] The main objective of this invention is to provide a composite material for editing the microstructure of MAX phase ceramics, its preparation method, and its applications, thereby overcoming the shortcomings of existing technologies. This invention employs the following technical solutions to achieve its objective: One aspect of the present invention provides a composite material for editing the microstructure of a MAX phase ceramic, comprising a MAX phase and a metal boride phase; The molecular formula of the MAX phase is M2AX, where M is selected from one or more combinations of the former transition metal group, A is any one or more combinations of S, Se, and Te elements, and X is any one or more combinations of C, S, Se, and P elements. The molecular formula of the metal boride phase is represented by MeB2, where Me is one or more combinations of group IVB and VB transition metals, and B represents boron.

[0006] Preferably, M is any one or more combinations of elements Ti, Zr, Hf, V, Nb, and Ta. Me is any one or more combinations of elements Ti, Zr, Hf, Nb, Ta, and V. Me and M may be the same or different.

[0007] Preferably, in the composite material, the volume percentage of the metal boride phase is 10-49 wt%, and the volume percentage of the MAX phase is 50-89 wt%. More preferably, the volume percentage of the metal boride phase is 30-45 wt%, and the volume percentage of the MAX phase is 54-69 wt%.

[0008] Preferably, the MAX phase has a layered hexagonal lattice with a space group of P63 / mmc, and the unit cell is formed by alternating stacking of M2X units and A atomic layers; the metal boride phase has a hexagonal crystal structure with a space group of P6 / mmm, and the unit cell is formed by alternating stacking of B atomic lattice network and metal atomic Me layers.

[0009] Preferably, the composite material is obtained by in-situ sintering of boride MAX material, M'' material and X material under high temperature and high pressure.

[0010] The molecular formula of the boride MAX material is M'2AB, where M' is selected from one or more combinations of elements from the early transition metal group, A is any one or more combinations of elements S, Se, and Te, and B represents boron. Preferably, M' is any one or more combinations of elements Ti, Zr, Hf, V, Nb, and Ta.

[0011] The M'' material is an elemental form of M'' or an alloy formed by multiple M'' elements. M'' is one or more combinations of elements from the pre-transition metal group. The M'' material can be a single elemental form of M'', a mixture of multiple elemental forms of M'', or an alloy formed by multiple M'' elements. Preferably, M'' is any one or more combinations of elements Ti, Zr, Hf, V, Nb, and Ta. M'' and M' can be the same element or different elements.

[0012] The X material is an elemental substance of X or a compound formed by multiple X elements, where X is any one or more combinations of C, S, Se, and P elements. The X material can be a single elemental substance of X, a mixture of multiple elemental substances of X, or a compound formed by multiple X elements.

[0013] Preferably, the molar ratio of boride MAX material, M'' material, and X material is 2:(0~1]:(0~2.5). (0~1] represents any number from 0 to 1, excluding 0 and including 1; (0~2.5] represents any number from 0 to 2.5, excluding 0 and including 2.5.

[0014] Preferably, the high-temperature and high-pressure reaction conditions include: a temperature of 1200–1700 °C, a pressure of 20–80 MPa, and a reaction time of 20–150 min. The preferred heating rate is 10–80 °C / min.

[0015] Using boride MAX material, M'' material, and X material as raw materials, a composite material including M2AX and MeB2 is formed by in-situ sintering under high temperature and high pressure conditions. The constituent elements of M2AX are derived as follows: M is derived from the inherent M' element in the boride MAX material, or M is derived from the combination of the M' element in the boride MAX material and the M'' element in the M'' material; the A element is derived from the inherent A element in the boride MAX material; and the X element is derived from the X element in the X material.

[0016] The nucleation site and growth material source of the metal boride are precisely controlled by the type and ratio of raw materials, thereby achieving directional regulation of the morphology of the metal boride-reinforcing phase.

[0017] Metal boride MeB2 in the lattice of boride MAX material (M'2AB) The constituent elements of the surface core are derived as follows: B comes from B in MAX boride materials; Me comes from the M' element in MAX boride materials and / or the M'' element in M'' materials.

[0018] The aspect ratio of the metal boride MeB2 can be adjusted.

[0019] A second aspect of this invention provides a method for preparing a composite material with MAX phase ceramic microstructure editing, comprising the following steps: Boride MAX material, M'' material and X material are mixed uniformly, and the resulting mixture is sintered in situ under an inert atmosphere and high temperature and high pressure conditions to obtain a composite material with MAX phase ceramic microstructure editing.

[0020] The inert atmosphere is nitrogen and / or argon.

[0021] The third aspect of this invention provides an application of composite materials with MAX phase ceramic microstructure editing in extreme environment fields such as advanced nuclear energy, aerospace, and marine engineering equipment.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The composite material with edited microstructure of MAX phase ceramics synthesized in this invention is a novel material, which is of great significance for supplementing the structure, types and control of microstructure of MAX phase composite materials. At the same time, the microstructure of the synthesized composite material with edited microstructure of MAX phase ceramics can be controlled by adjusting the content and type of M-site and X-site elements, thereby realizing the on-demand customization of core properties such as fracture toughness, hardness and flexural strength, providing support for its customized application in extreme environments such as advanced nuclear energy, aerospace, and marine engineering equipment.

[0023] (2) This invention pioneers a synthesis route of "MX sublayer substitution + in-situ self-generated reinforcing phase": using the boride MAX phase as a precursor, by precisely introducing additional metal (M'') and non-metal (X) elements, the in-situ synthesis of the target MAX phase and the in-situ generation and morphology control of the metal boride reinforcing phase are simultaneously achieved in a single-step high-temperature and high-pressure sintering process. This is a novel material design and preparation strategy. The entire preparation method is simple, low-consumption, and universally applicable, providing a new strategy for the synthesis of other novel MAX phase composite materials.

[0024] (3) The composite material with edited microstructure of MAX phase ceramic provided by the present invention has undergone significant changes in microstructure compared with existing MAX phase materials and MAX phase composite materials due to the introduction of second phase metal borides and MX substitution of the MAX phase during the synthesis process. This results in changes in the physical and chemical properties of the MAX phase material. For example, the ZrB2 / Zr2SeC composite material prepared in Example 1 has good mechanical and tribological properties; its hardness can reach 7 GPa, which is 64% higher than that of Zr2SeC material, and its fracture toughness is about 7 MPa·m. 1 / 2 Compared to Zr2SeC materials, this represents a 114% improvement. This invention achieves a significant toughening and reinforcing effect by introducing an in-situ grown lath-shaped metal boride second phase.

[0025] In summary, compared with existing MAX phase composite materials, the MAX phase ceramic microstructure-edited composite material provided by this invention has a series of advantages such as high strength, high hardness, good fracture toughness, oxidation resistance, high temperature resistance, high damage tolerance and machinability. Moreover, the preparation process is simple and easy to operate, and it has potential application prospects in extreme environment fields such as advanced nuclear energy and aerospace. Attached Figure Description

[0026] Figure 1 These are the XRD patterns and Rietveld full-spectrum analysis results of the composite material with MAX phase ceramic microstructure edited in Example 1 of this invention; Figure 2 These are SEM images and elemental distribution diagrams of the surface polished composite material with MAX phase ceramic microstructure edited in Example 1 of this invention; Figure 3 This is the electron backscatter diffraction (EBSD) pattern of the ZrB2 / Zr2SeC composite material in Example 1 of this invention; Figure 4 This is a SEM image of the fracture surface of the composite material with edited MAX phase ceramic microstructure in Example 1 of this invention; Figure 5 These are the XRD patterns and Rietveld full-spectrum analysis results of the composite material with MAX phase ceramic microstructure edited in Example 2 of this invention; Figure 6 These are SEM images and elemental distribution diagrams of the surface polished composite material with MAX phase ceramic microstructure edited in Example 2 of this invention. Detailed Implementation

[0027] In the description of this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, and includes both a and b. "Multiple" includes two, three, four, five, or more.

[0028] The technical solution of the present invention will be further described and illustrated below with reference to specific embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of helping to understand the present invention and are not intended to limit the specific scope of the present invention. Furthermore, the accompanying drawings used herein are merely for better illustrating the content disclosed in the present invention and do not limit the scope of protection. Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commonly used in the art, and the methods used in the embodiments are all conventional methods in the art.

[0029] Example 1 In this embodiment, the composite material for editing the microstructure of MAX phase ceramics is a ZrB2 / Zr2SeC bulk material.

[0030] The preparation method of this ZrB2 / Zr2SeC bulk material is as follows: (1) Weigh 5.5 g of Zr2SeB powder, 0.81 g of 400 mesh zirconium powder and 0.22 g of 300 mesh graphite powder, grind and mix the above materials to obtain a mixture.

[0031] (2) After pressing the mixture into sheets using a graphite mold, it was placed in a spark plasma sintering system for reaction. The reaction conditions were: reaction temperature 1600 ℃, holding time 30 min, argon inert atmosphere protection, heating rate 50 ℃ / min, and pressure 50 MPa. After the sintering system temperature dropped to room temperature, the reaction product was removed from the graphite mold.

[0032] (3) Remove the graphite paper from the surface of the obtained block, then polish it to a mirror finish with sandpaper of different mesh sizes, place it in a 50 ℃ oven, and take it out after 12 h to obtain the block material.

[0033] The bulk material processed in step (3) was examined using X-ray diffraction (XRD), such as... Figure 1 As shown, R can be obtained through full-spectrum analysis using the Rietveld method. wp =15.957%, proving that the method successfully synthesized composite materials with MAX phase ceramic microstructure editing. A small amount of zirconium oxide and zirconium carbide impurities appeared in the solid. The former may be from the oxidation of zirconium during the preparation process, and the latter is from the by-product obtained from the reaction of zirconium and graphite.

[0034] The block after step (3) was observed using a scanning electron microscope (SEM), such as... Figure 2As shown, the synthesized bulk material exhibits a typical MAX phase layered structure for Zr₂SeC and a lath structure for ZrB₂. Energy dispersive spectroscopy (EDS) analysis further verifies the above hypothesis. As shown in Table 1, the gray matrix of the bulk material is composed of Zr, Se, and C, with the atomic percentage ratio of Zr to Se at the M site being 2.37, approximately 2. As shown in Table 2, the dark black striped regions of the bulk material are composed of Zr and B, with the atomic percentage ratio of Zr to B being 0.46, approximately 0.5, consistent with the experimental design and XRD analysis.

[0035] Table 1: Energy dispersive spectral analysis results of the gray matrix locations in the block obtained in Example 1 element Zr Se C B at.% 32.7 13.8 44.5 0.2 Table 2: Energy dispersive spectroscopy (EDS) results of the black stripe locations in the block obtained in Example 1 element Zr Se C B at.% 23.6 5.4 20.2 50.9 Figure 3 The image shows the electron backscatter diffraction (EBSD) pattern of ZrB2 / Zr2SeC. It can be seen that in the composite material, ZrB2 accounts for 38% of the volume and Zr2SeC accounts for 61.7% of the volume.

[0036] Figure 4 The image shows the fracture surface SEM image of the ZrB2 / Zr2SeC composite material. It can be seen that the ZrB2 phase exhibits a lamellar morphology, while the Zr2SeC phase exists in the form of a blocky matrix. The lamellar ZrB2 phase is dispersed and embedded in the Zr2SeC matrix, and the interface is in close contact. The interfacial bonding between the two is good, and the material has a high density.

[0037] Its Vickers hardness was determined to be approximately 7 GPa using the Vickers hardness indentation method, its flexural strength reached 226 MPa using the three-point bending test, and its fracture toughness was approximately 7 MPa·m using the single-sided pre-cracked beam method. 1 / 2 .

[0038] Example 2 In this embodiment, the composite material for editing the microstructure of the MAX phase ceramic is ZrB2 / (Zr 0.82 Hf 0.18 )2SeC bulk material.

[0039] The ZrB2 / (Zr 0.82 Hf 0.18 The preparation method of 2SeC bulk is as follows: (1) Weigh 5g of the solid product Zr2SeB powder, 1.47g of 400-mesh hafnium powder and 0.22g of 300-mesh graphite powder, grind and mix the above materials to obtain a mixture.

[0040] (2) After pressing the mixture into sheets using a graphite mold, it was placed in a spark plasma sintering system for reaction. The reaction conditions were: reaction temperature 1700℃, holding time 30 min, argon inert atmosphere protection, heating rate 50℃ / min, and pressure 50 MPa. After the sintering system temperature dropped to room temperature, the reaction product was removed from the graphite mold.

[0041] (3) Remove the graphite paper from the surface of the obtained block, then polish it to a mirror finish with sandpaper of different mesh sizes, put it in a 50°C oven, and take it out after 12 hours to obtain the block material.

[0042] The bulk material processed in step (3) was examined using X-ray diffraction (XRD), such as... Figure 5 As shown, R can be obtained through full-spectrum analysis using the Rietveld method. wp =15.957%, proving that this method successfully synthesized in-situ enhanced ZrB2 / (Zr) boride ZrB2. 0.82 Hf 0.18 In the 2SeC composite material, a small amount of zirconium oxide and zirconium carbide impurities appeared in the solid. The former may have come from the oxidation of zirconium during the preparation process, while the latter came from the byproducts obtained from the reaction of zirconium and graphite.

[0043] The block after step (3) was observed using a scanning electron microscope (SEM), such as... Figure 6 As shown, in this bulk material, the gray matrix is ​​identified as (Zr... 0.82 Hf 0.18 )2SeC, the dark black stripes are ZrB2. It can be found that the micromorphology of ZrB2 has changed significantly, with both its size and aspect ratio increasing. Therefore, the micromorphology of composite materials with MAX phase ceramic microstructure editing can be changed by adjusting the microstructure.

[0044] Its Vickers hardness was approximately 7 GPa obtained by Vickers indentation method, its flexural strength reached 257 MPa by three-point bending test, and its fracture toughness was approximately 6.5 MPa·m by single-sided pre-cracked beam method. 1 / 2 .

[0045] Example 3 In this embodiment, the composite material for editing the microstructure of MAX phase ceramics is a bulk material of HfB2 / Hf2SeC.

[0046] The preparation method of the HfB2 / Hf2SeC bulk material is as follows: (1) Weigh 6.2 g of the solid product Hf2SeB powder, 1.63 g of 400 mesh hafnium powder and 0.22 g of 300 mesh graphite powder, grind and mix the above materials to obtain a mixture.

[0047] (2) After pressing the mixture into sheets using a graphite mold, it was placed in a spark plasma sintering system for reaction. The reaction conditions were: reaction temperature 1700℃, holding time 35 min, argon inert atmosphere protection, heating rate 40 ℃ / min, and pressure 60 MPa. After the sintering system temperature dropped to room temperature, the reaction product was removed from the graphite mold.

[0048] (3) Remove the graphite paper from the surface of the obtained block, then polish it to a mirror finish with sandpaper of different mesh sizes, place it in a 60 ℃ oven, and take it out after 10 h to obtain the block material.

[0049] Example 4 In this embodiment, the composite material for editing the microstructure of MAX phase ceramics is (Zr 0.4 Ti 0.6 )B2 / (Zr 0.95 Ti 0.05 )2SeC bulk material.

[0050] The (Zr) 0.4 Ti 0.6 )B2 / (Zr 0.95 Ti 0.05 The preparation method of 2SeC bulk is as follows: (1) Weigh 5 g of the solid product Zr2SeB powder, 0.4 g of 400 mesh titanium powder and 0.22 g of 300 mesh graphite powder, grind and mix the above materials to obtain a mixture.

[0051] (2) After pressing the mixture into sheets using a graphite mold, it was placed in a spark plasma sintering system for reaction. The reaction conditions were: reaction temperature 1400 ℃, holding time 30 min, argon inert atmosphere protection, heating rate 50 ℃ / min, and pressure 50 MPa. After the sintering system temperature dropped to room temperature, the reaction product was removed from the graphite mold.

[0052] (3) Remove the graphite paper from the surface of the obtained block, then polish it to a mirror finish with sandpaper of different mesh sizes, place it in a 50 ℃ oven, and take it out after 12 h to obtain the block material.

[0053] Its Vickers hardness was approximately 8 GPa obtained by Vickers indentation method, its flexural strength reached 174 MPa by three-point bending test, and its fracture toughness was approximately 5.6 MPa·m by single-sided pre-cracked beam method. 1 / 2 .

[0054] Example 5 In this embodiment, the composite material for editing the microstructure of MAX phase ceramics is a NbB2 / Nb2SeC bulk material.

[0055] The preparation method of the NbB2 / Nb2SeC bulk material is as follows: (1) Weigh 4.8 g of the solid product Nb2SeB powder, 0.4 g of 400 mesh niobium powder and 0.22 g of 300 mesh graphite powder, grind and mix the above materials to obtain a mixture.

[0056] (2) After pressing the mixture into sheets using a graphite mold, it was placed in a spark plasma sintering system for reaction. The reaction conditions were: reaction temperature 1200 ℃, holding time 40 min, argon inert atmosphere protection, heating rate 55 ℃ / min, and pressure 70 MPa. After the sintering system temperature dropped to room temperature, the reaction product was removed from the graphite mold.

[0057] (3) Remove the graphite paper from the surface of the obtained block, then polish it to a mirror finish with sandpaper of different mesh sizes, put it in a 70 ℃ oven, and take it out after 9 h to obtain the block material.

[0058] Example 6 In this embodiment, the composite material for editing the microstructure of the MAX phase ceramic is NbB2 / (Nb 0.8 V 0.2 )2SeC bulk material.

[0059] The NbB2 / (Nb 0.8 V 0.2 The preparation method of 2SeC bulk is as follows: (1) Weigh 4.8 g of the solid product Nb2SeB powder, 0.4 g of 400 mesh vanadium powder and 0.22 g of 300 mesh graphite powder, grind and mix the above materials to obtain a mixture.

[0060] (2) After pressing the mixture into sheets using a graphite mold, it was placed in a spark plasma sintering system for reaction. The reaction conditions were: reaction temperature 1200 ℃, holding time 45 min, argon inert atmosphere protection, heating rate 40 ℃ / min, and pressure 30 MPa. After the sintering system temperature dropped to room temperature, the reaction product was removed from the graphite mold.

[0061] (3) Remove the graphite paper from the surface of the obtained block, then polish it to a mirror finish with sandpaper of different mesh sizes, place it in a 65 ℃ oven, and take it out after 11 h to obtain the block material.

[0062] Example 7 In this embodiment, the composite material for editing the microstructure of MAX phase ceramics is a ZrB2 / Zr2SC bulk material.

[0063] The preparation method of this ZrB2 / Zr2SC bulk material is as follows: (1) Weigh 4.8g of Zr2SB powder, 0.81g of 400-mesh zirconium powder and 0.22g of 300-mesh graphite powder, grind and mix the above materials to obtain a mixture.

[0064] (2) After pressing the mixture into sheets using a graphite mold, it was placed in a spark plasma sintering system for reaction. The reaction conditions were: reaction temperature 1500 ℃, holding time 30 min, argon inert atmosphere protection, heating rate 40 ℃ / min, and pressure 55 MPa. After the sintering system temperature dropped to room temperature, the reaction product was removed from the graphite mold.

[0065] (3) Remove the graphite paper from the surface of the obtained block, then polish it to a mirror finish with sandpaper of different mesh sizes, place it in a 45 ℃ oven, and take it out after 14 h to obtain the block material.

[0066] Example 8 In this embodiment, the composite material for editing the microstructure of MAX phase ceramics is a bulk HfB2 / Hf2TeC material.

[0067] The preparation method of this HfB2 / Hf2TeC bulk material is as follows: (1) Weigh 5.6g of Hf2TeB powder, 1.00g of 400-mesh hafnium powder and 0.14g of 300-mesh graphite powder, grind and mix the above materials to obtain a mixture.

[0068] (2) After pressing the mixture into sheets using a graphite mold, it was placed in a spark plasma sintering system for reaction. The reaction conditions were: reaction temperature 1500℃, holding time 50 min, argon inert atmosphere, heating rate of 55℃ / min, and pressure of 60 MPa. After the sintering system temperature dropped to room temperature, the reaction product was removed from the graphite mold.

[0069] (3) Remove the graphite paper from the surface of the obtained block, then polish it to a mirror finish with sandpaper of different mesh sizes, place it in a 50 ℃ oven, and take it out after 12 h to obtain the block material.

[0070] Example 9 In this embodiment, the composite material for editing the microstructure of MAX phase ceramics is a ZrB2 / Zr2SeP bulk material.

[0071] The preparation method of this ZrB2 / Zr2SeP bulk material is as follows: (1) Weigh 5.6 g of the solid product Zr2SeB powder, 0.81 g of 400 mesh zirconium powder and 0.66 g of red phosphorus, grind and mix the above materials to obtain a mixture.

[0072] (2) After pressing the mixture into sheets using a graphite mold, it was placed in a spark plasma sintering system for reaction. The reaction conditions were: reaction temperature 1500 ℃, holding time 30 min, argon inert atmosphere, protective heating rate of 50 ℃ / min, and pressure of 50 MPa. After the sintering system temperature dropped to room temperature, the reaction product was removed from the graphite mold.

[0073] (3) Remove the graphite paper from the surface of the obtained block, then polish it to a mirror finish with sandpaper of different mesh sizes, place it in a 50 ℃ oven, and take it out after 12 h to obtain the block material.

[0074] Example 10 In this embodiment, the composite material for editing the microstructure of the MAX phase ceramic is ZrB2 / Zr2(S) 0.5 Se 0.5 C-block material.

[0075] The ZrB2 / Zr2(S) 0.5 Se 0.5 The preparation method of bulk material C is as follows: (1) Weigh out the solid product Zr2(S) 0.5 Se 0.5 5.5 g of B powder, 0.81 g of 400-mesh zirconium powder, and 0.22 g of 300-mesh graphite powder were ground and mixed to obtain a mixture.

[0076] (2) After pressing the mixture into sheets using a graphite mold, it was placed in a spark plasma sintering system for reaction. The reaction conditions were: reaction temperature 1500 ℃, holding time 30 min, argon inert atmosphere, protective heating rate of 50 ℃ / min, and pressure of 50 MPa. After the sintering system temperature dropped to room temperature, the reaction product was removed from the graphite mold.

[0077] (3) Remove the graphite paper from the surface of the obtained block, then polish it to a mirror finish with sandpaper of different mesh sizes, place it in a 50 ℃ oven, and take it out after 12 h to obtain the block material.

[0078] In addition, the inventors also conducted relevant experiments using other raw materials and process conditions described in this specification instead of the corresponding raw materials and process conditions in Examples 1-10 above. The results all showed that composite materials with MAX phase ceramic microstructure editing could be obtained.

[0079] Comparative Example 1 Comparative Example 1 tested the relevant mechanical properties of Zr2SeC: Its Vickers hardness was approximately 5 GPa obtained by Vickers indentation method, its flexural strength reached 260 MPa by three-point bending test, and its fracture toughness was approximately 3.2 MPa·m by single-sided pre-cracked beam method.1 / 2 .

[0080] Comparative Example 2 In the preparation process of Comparative Example 2, Zr2SeC powder and ZrB2 powder were directly mixed and sintered. All other aspects were the same as in Example 1. The specific preparation method is as follows: (1) Weigh 4 g of Zr2SeC powder and 0.83 g of 400 mesh ZrB2 powder, grind and mix the above materials to obtain a mixture.

[0081] (2) After pressing the mixture into sheets using a graphite mold, it was placed in a spark plasma sintering system for reaction. The reaction conditions were: reaction temperature 1600 ℃, holding time 30 min, argon inert atmosphere protection, heating rate 50 ℃ / min, and pressure 50 MPa. After the sintering system temperature dropped to room temperature, the reaction product was removed from the graphite mold.

[0082] (3) Remove the graphite paper from the surface of the obtained block, then polish it to a mirror finish with sandpaper of different mesh sizes, place it in a 50 ℃ oven, and take it out after 12 h to obtain the block material.

[0083] The composite material obtained in Comparative Example 2 was ZrB2 / Zr2SeC.

[0084] Its Vickers hardness was approximately 5 GPa obtained by Vickers indentation method, its flexural strength reached 83 MPa by three-point bending test, and its fracture toughness was approximately 3.9 MPa·m by single-sided pre-cracked beam method. 1 / 2 .

[0085] All aspects, embodiments, and features of this invention should be considered illustrative in all respects and not limiting of the invention; the scope of the invention is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0086] In the preparation method of this invention, the order of the steps is not limited to the listed order. For those skilled in the art, variations in the order of the steps without creative effort are also within the scope of protection of this invention. Furthermore, two or more steps or actions can be performed simultaneously.

[0087] Finally, it should be noted that the specific embodiments described herein are merely illustrative examples of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A composite material with microstructure edited MAX phase ceramics, characterized in that, The composite material comprises a MAX phase and a metal boride phase; The molecular formula of the MAX phase is M2AX, where M is selected from one or more combinations of the former transition metal group, A is any one or more combinations of S, Se, and Te elements, and X is any one or more combinations of C, S, Se, and P elements. The molecular formula of the metal boride phase is MeB2, where Me is one or more combinations of group IVB and VB transition metals, and B represents boron.

2. The composite material according to claim 1, characterized in that, M is any one or more combinations of elements Ti, Zr, Hf, V, Nb, and Ta; Me is any one or more combinations of elements Ti, Zr, Hf, Nb, Ta, and V.

3. The composite material according to claim 1, characterized in that, In the composite material, the volume percentage of the metal boride phase is 10-49 wt%, and the volume percentage of the MAX phase is 50-89 wt%.

4. The composite material according to claim 1, characterized in that, The composite material is obtained by in-situ sintering of boride MAX material, M'' material and X material under high temperature and high pressure. The molecular formula of the boride MAX material is M'2AB, where M' is selected from one or more combinations of the former transition metal group, A is any one or more combinations of S, Se, and Te elements, and B represents the element boron. The M'' material is an elemental substance of M'' or an alloy formed by the element M'', where M'' is one or more combinations of elements from the former transition metal group; The X material is an elemental substance of X or a compound formed by the element X, where X is any one or more combinations of the elements C, S, Se, and P.

5. The composite material according to claim 4, characterized in that, M' can be any one or more combinations of the elements Ti, Zr, Hf, V, Nb, and Ta; M'' can be any one or more combinations of the elements Ti, Zr, Hf, V, Nb, and Ta.

6. The composite material according to claim 4, characterized in that, The molar ratio of boride MAX material, M'' material, and X material is 2:(0~1]:(0~2.5]. And / or, high temperature and high pressure reaction conditions include: temperature of 1200-1700 ℃, pressure of 20-80 MPa, and reaction time of 20-150 min.

7. The composite material according to claim 4, characterized in that, The constituent elements of M2AX are derived as follows: M is derived from the inherent M' element in the boride MAX material, or M is derived from the combination of the M' element in the boride MAX material and the M'' element in the M'' material; the A element is derived from the inherent A element in the boride MAX material; and the X element is derived from the X element in the X material.

8. The composite material according to claim 4, characterized in that, The nucleation sites and material sources of the metal boride MeB2 are precisely controlled, thereby achieving directional regulation of the morphology of the metal boride-reinforcing phase. Metal boride MeB2 in the {10} lattice of boride MAX material (M'2AB) The 0} surface core, whose constituent elements are derived as follows: B comes from B in boride MAX materials; Me comes from the M' element in boride MAX materials and / or the M'' element in M'' materials; The aspect ratio of the metal boride MeB2 can be adjusted.

9. The method for preparing a composite material with MAX phase ceramic microstructure editing as described in claim 1, characterized in that, Includes the following steps: Boride MAX material, M'' material and X material are mixed uniformly, and the resulting mixture is sintered in situ under an inert atmosphere and high temperature and high pressure conditions to obtain a composite material with MAX phase ceramic microstructure editing.

10. The application of the composite material with MAX phase ceramic microstructure editing as described in claim 1 in advanced nuclear energy, aerospace, and marine engineering equipment.

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